2020-II-09

Ans: A
Let $\$P$ be the selling price of the toy. Then the cost of the toy

$\begin{array}{cl}
= & P \times (1- x\%) \\
\end{array}$

Since the percentage profit is $25\%$, we have

$\begin{array}{rcl}
\dfrac{P – P\times(1- x\%)}{P\times (1 – x\%)} \times 100 \% & = & 25\% \\
\dfrac{x\%}{1-x\%} & = & 0.25 \\
\dfrac{x}{100} & = & 0.25 – \dfrac{0.25x}{100} \\
x & = & 25 – 0.25x \\
1.25x & = & 25 \\
x & = & 20
\end{array}$